Rheumatoid arthritis is a disorder that causes joint swelling and pain in the hands and feet, as the autoimmunity affects the joints in the hands and feet. As the disorder progresses, bone and cartilage destruction causes joint stiffness, thereby severely affecting the daily lives.
Rheumatoid arthritis had been a refractory disorder, the etiology and the pathology of which were unknown, and that could not be prevented or cured. In recent years, however, as the pathology has been elucidated, inhibition of T cells or inflammatory cytokines has been found to provide a significant amelioration. Accordingly, the use of a suitable combination of therapeutic agents has allowed for targeting, as a specific therapeutic objective, inhibition of joint destruction, even if slightly, and remission where the symptoms are controlled.
Pharmaceutical agents used in drug therapy against rheumatoid arthritis are broadly classified into non-steroidal anti-inflammatory drugs (NSAIDS), which have analgesic, antipyretic and anti-inflammatory effects and nonspecifically suppress inflammatory response; steroid drugs, which rapidly and effectively suppress inflammation due to rheumatoid arthritis and significantly improve the QOL in patients suffering from rheumatoid arthritis with active lesions; antirheumatic drugs (disease modifying antirheumatic drugs: DMARDs), which do not have the effect of suppressing inflammation itself, but alleviate immune abnormality associated with rheumatoid arthritis to control the activity of rheumatoid arthritis; and biological drugs, which are antibodies or fusion proteins developed by genetic engineering techniques in order to selectively inhibit a cytokine or the like intimately involved in the pathology of rheumatoid arthritis.
There are no pharmaceutical agents for rheumatoid arthritis, the agents having all of the effect of inducing remission of rheumatic inflammation, the effect of inhibiting the progression of joint destruction, and rapid effects. And some of the agents have strong side effects, and others of the agents have mild side effects. Thus, these pharmaceutical agents are used in complementary combination in the drug therapy.
Among the above pharmaceutical agents, antirheumatic drugs are classified into immunomodulatory drugs, which correct abnormal immune function without affecting normal immune function (for example, see Patent Literature 1), and immunosuppressive drugs, which nonspecifically suppress overall immune function (for example, Patent Literature 2), based on its mechanism of action.